1. Field of the Invention
The present invention concerns the medical-surgical field, in particular arterial pathology, but also more generally the pathology of other anatomical canals, such as the venous, biliary and urinary canals, its object being an autoexpandable vascular endoprosthesis of permanent elasticity and only slight shortening upon insertion into the canals, as well as a device for the use thereof.
2. Description of the Related Art
In the present state of the art, endolumenal arterial prostheses already exist, referred to in the international medical literature by the English expression "stent".
These prostheses are of two types:
ones of nonelastic metallic material expandable from the inside towards the outside under the effect of an inflatable balloon; PA1 others of elastic metallic material formed of metal meshes; they are introduced stretched into the lumen of the vessel and their diameter increases when the longitudinal extension is relaxed. PA1 those of the first type must be carefully adjusted on a balloon since, once expanded, they can no longer be withdrawn; PA1 those of the second type do not have this drawback, but the structure of their meshes requires substantial longitudinal extension in order to reduce their diameter, a condition indispensable in order to be able to introduce them into a vessel; once introduced, their retraction within the vessel is also very substantial, resulting in difficulties in adjustment and in rubbing on the walls of the vessel over a length of several centimeters.
These prostheses have various drawbacks: